Electric switch.



` citizen of the DUDLEY T. FISI-IEB, F COLUMBUS,

TUBINGV COMPANY,

GEIQ,

nnncrnic ASSIGNOR A? CORPORATION OF OHIO.

'ro rue marmer :ranuras- SWITCE.

Application med lmmber 1 all whom it may concern:

Be it known that I, DUDLEI T. Freuen, a

United States, Lresiding at Columbus, in the county of'Frgmklin and State of Ohio, have invented; certain new and useful Improvements in Electric Switches, of

which the following is a cation, reference being had therein togthe accompanying drawing.

This invention relates improvements in switches and connecting devices for electric d conductors and is primarily intended :for use in mines or other places where an atmosphere of explosive gases is frequently met wit i.

A switch embodying my improvements may be used either as an element in the per marient mine equipment or it may form a art of movable apparatus.`

It is well known that mine explosions are frequently caused by electric sparks from various sources, and it is the object of this invention to provide a switch in which there will be no poss'bility of sparking.

Other objects of the invention are to pro vide various improvements in structure, which are set forth in the following specification. I

In the accompanying drawings forming a partk of this specification, I have shown one embodiment of my invention. I do not desire, however, to be limited to the exact construction which I have shown, understood that various changes may be ma de within the scope of my invention.

Ot the drawingFigure l is a cross sec tional plan view taken along the line 1-l of Fig. B. Fig.

A 2 is a cross sectional plan view taken along the line .2-2 of Fig. 3. Fig. 3

' is a cross sectional elevation taken along the l. Fig. 4 is an elevation. Referring to the drawings, l represents the casing which comprises the upper section 2 and the lower section 3. The two sec- Ations are provided with suitable lugs, through which pass the connecting bolts line Sw-3 of Fig.

5 is a plate or slab of suitable insulating material, such as slate. This slab is held in place between the two casing sections and serves as a support for the various parts to be hereinafter described. This slab serves Specicat-ion or Letters Patent.

suitable aperture in the and it will be 1 Patented June 8, 1955.

0, 1909. Serial R0. 527.299.

as a cover for the lower half of the casing andf forms in combination with' it va gaetight and flame-proof chamber.

6 is an operating shaft which extends through a suitable aperture in the top of the casing.y and is provided with an' operating handle 7. l

8 is ahub secured to the shaft 6 by means of the pin 9. The hub is 4iournaled in a. plate 5'.V The lower end ci the shaft is provided with the bearing ring l0, which is journaled in a' bearing on the bottom of the casing. Between ythe hub 8 and the ring 10 the shaft 6 is preferably square and is surrounded by an insulating sleeve 1l. At dach end ofthis square section are provided two disks or washers 2, 13 of insulating material and having square central apertures adapted to engagel the sleeve on the shaft. To the square part of the .shaft 6 between the two insulating washers are clamped the two contact supr ports le and 15. These two supports are held in place by the two bolts 16 and 17, which pass through the ilanged sleeves l8-\ 18 mounted in suitable apertures in the sup ports. The contact segments i9 and i0 are fastened to the supports la and l5 by means of screws. By the construction which has been described, each oif Jdie two Contact seg-- ments is completely insulated from the other.

2l, 252, and 24; are brushes, spring i'uounted on suitable brackets attached to the plate 5. They are so located that when the operating shaft is the position shown in- Fig. l electrical connection will be estab lished by the Contact segments between the brushes 2l and 22 and between the brushes and 24. On the upper side of the plate or slab 5 are vlocated the four terminal brackets 25, Q6, 27 and 28. Of these brackets, 25 is connected through the slab 5 u to the'brush 22, while the bracket Q6 is conpected to the brush 2li. 25 and 26 are conductor wires attached to the brackets 25 and 26. These enter the casing through the gas-tight seals 29 and 50. The brackets 27 and Q8 are attached to the brushes Qiand 23 respectively. They are provided with horizontal parallel studs 31, 3l, eachof which is preferably split throughout a portion. of

its length. @pposite to these studs 3l, 31,v there are located in the casing two apertures 32, 32.` 33, 33 are terminal plugsto side of the upper half of the casing. It is y held in place and guided by the vertical flanges or Walls 36, 36. Near its bottom this aro shutter is provided with a series of rack teeth 37, which engage with a. segmental pinion 38, formed preferably als a part of the hub 8. By means of this rack and pinion, the shutter is moved when the shaft 6 is turned. The shutter 36 is provided with a longitudinal slot 39, of a less width than the diameter of the plugs 33, 38. An nulargrooves are formed in the plugs,

and the edges of the slot in the shutter engage these grooves. At l-l and 42 the slot 39 is enlarged to a size slightly greater than the cross sectional area of the plugs.

The operation of the switch is as follows: W'henthe various parts are yin the position shown in the drawings, electrical connection is established on one side from the wire 26 through the brush 24, the segment 20, the brush 23, and the bracket 28 tothe plug 33. In a similar way, on the other side, connection is established from the conductor wire 25a to the other plug 33. vWith the parts in this position, the shutter 35 is located at one end of its line of travel, and the narrow parts of the` slot in the shutter engage the grooves in the plugs and prevent their withdrawal from the casing. When the switch is' turned so that the connection is broken between the brushes, the enlarged parts of the slot 39 are brought into alinement with the plugs and they may be withdrawn from the casing at will.- By means of this automatically locking feature it is made impossible for the plugs to be accidentally vwithdrawn when the current is passing through the wires. I prefer toiill the lower half of the lcasing withv oil and -thus prevent all s arks between the brushes and the contacts.

ven, if this is not done, however,` the lower half of the casing is flame-proof, and any sparks formed therein cannot be communicated to the outer atmosphere to cause an explosion. It Will be noted that in' addiltion to making the switch itself flame-proof,

l have made it impossible for any sparks to be caused by the disconnecting of the terminal plugs.

1. In an electric switch, the combination of a casing, a division slab in said casing forming a flame-proof chamber in one part thereof, an operating, spindle extending through the slab, a contact making and breaking device connected to the spindle and located Within the flame-proof chamber, terminals in the casing outside of the flameprocf chamber and connected to the contact device, conductor plugs adapted to engage the terminals through suitable apertures m the casing, a shutter adapted to engage the plugs when in one position ,and to Ydisengage them when in another, a 'rack on the shutter, and a pinion on the spindle engaging the 'rack whereby the shutter is moved into its lplug-engaging'or its plug-disengag ing position in accordance with whether the contact device is in its contact `making or its contact breaking position, substantially as set forth.

y2. In, an electricswitch, the combination of a casing, an operating shaftrotatable inthe casing, one-part of the said shaft being square, an insulating sleevel on the square part of the shaft, two Contact segments each adapted to lengage a corner of the bushing, clamping bolts betweenv the two rounding the said bolts, and contact brushes adhpted to engage the segments, substantially as set forth.

3. Inan electric switch the combination of a casing provided with a wall dividing the casing into two chambers, one of which is flame proof, a spindle extending through the said dividing wall and adapted to oscillate about its axis, contact devices connected I L. Hornms, G. B- Norms.

l contactingV segments, insulating sleeves sur- 

